When a vdb is created in Designer 8.5 and includes a data-role, this adds to the vdb.xml the grant-all element. This element is not applicable to Designer versions older that 8.5 hence any attempt to open this vdb in Designer 8.3.4 results in a cvc exception. Rather than allowing display of a cryptic error, it would be better to display a warning/error message that the vdb concerned is not compatible with the older version of Designer due to the grant-all element.

Create a generic framework that can be plugged into such errors so that a standard message can be returned and it becomes trivial to insert checks into older Designer versions for 'future' functionality.